Create an expression for calculating On Time In Full

Hi,

I have done my first simple QW report to measure Delivery Performance for my Suppliers. As a first attempt I did a simple if expression that compared confirmed date with Good receit date. This works fine and looks as follows:

If

((ConfirmedDate-GRdate) >0, 0, 1) as DP,

Basically this will mean that all early deliveries will be measured as on time. I would now like to alter that expression so that it provides an On Time measure with no tolerance for early deliveries. My attempt was as follows: